Expose page_count in pagination api. (#6982)

* Expose page_count in pagination api.

Fixes #6919

* Add docs

docs/topics/api/overview.rst

@@ -98,6 +98,7 @@ The following properties will be available in paginated responses:
 * *next*: the URL for the next page in the pagination.
 * *previous*: the URL for the previous page in the pagination.
 * *page_size*: The number of items per page in the pagination.
+* *page_count*: The number of pages available in the pagination.
 * *count*: the total number of records.
 * *results*: the array containing the results for this page.
 

src/olympia/api/pagination.py

@@ -17,6 +17,7 @@ class CustomPageNumberPagination(PageNumberPagination):
             # Note that self.page_size doesn't work, it contains the default
             # page size.
             ('page_size', self.page.paginator.per_page),
+            ('page_count', self.page.paginator.num_pages),
             ('count', self.page.paginator.count),
             ('next', self.get_next_link()),
             ('previous', self.get_previous_link()),
@@ -42,6 +43,7 @@ class OneOrZeroPageNumberPagination(CustomPageNumberPagination):
         # return next/prev links.
         return Response(OrderedDict([
             ('page_size', 1),
+            ('page_count', 1),
             ('count', len(data)),
             ('next', None),
             ('previous', None),

src/olympia/api/tests/test_pagination.py

@@ -31,6 +31,7 @@ class TestCustomPageNumberPagination(TestCase):
         assert response.status_code == status.HTTP_200_OK
         assert response.data == {
             'page_size': 10,
+            'page_count': 10,
             'results': range(11, 21),
             'previous': 'http://testserver/?page_size=10',
             'next': 'http://testserver/?page=3&page_size=10',
@@ -43,6 +44,7 @@ class TestCustomPageNumberPagination(TestCase):
         assert response.status_code == status.HTTP_200_OK
         assert response.data == {
             'page_size': 25,
+            'page_count': 4,
             'results': range(1, 26),
             'previous': None,
             'next': 'http://testserver/?page=2',
@@ -66,6 +68,7 @@ class TestESPageNumberPagination(TestCustomPageNumberPagination):
         response = view(request)
         assert response.data == {
             'page_size': 5,
+            'page_count': 5000,
             'results': mock.ANY,
             'previous': 'http://testserver/?page=4998&page_size=5',
             'next': 'http://testserver/?page=5000&page_size=5',
@@ -76,6 +79,7 @@ class TestESPageNumberPagination(TestCustomPageNumberPagination):
         response = view(request)
         assert response.data == {
             'page_size': 5,
+            'page_count': 5000,
             'results': mock.ANY,
             'previous': 'http://testserver/?page=4999&page_size=5',
             'next': None,
@@ -99,6 +103,7 @@ class TestOneOrZeroPageNumberPagination(TestCase):
         response = self.view(request)
         assert response.data == {
             'page_size': 1,
+            'page_count': 1,
             'results': range(1, 2),
             'previous': None,
             'next': None,
@@ -115,6 +120,7 @@ class TestOneOrZeroPageNumberPagination(TestCase):
         response = self.view(request)
         assert response.data == {
             'page_size': 1,
+            'page_count': 1,
             'results': [],
             'previous': None,
             'next': None,